<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <!-- 事件委托 -->
      <div @mouseleave="handleLeave"  @mouseenter="show = true">
        <h2 class="all">全部商品分类</h2>
        <!-- 三级联动 -->
        <transition name="fade">
          <div class="sort" @click="goSearch" v-show="show">
          <div class="all-sort-list2">
            <div
              :class="['item', { cur: currentIndex === index }]"
              v-for="(item1, index) in cateList"
              :key="item1.categoryId"
              @mouseenter="changItemStyle(index)"
            >
              <h3>
                <a :data-categoryName="item1.categoryName" :data-category1id="item1.categoryId">{{ item1.categoryName }}</a>
              </h3>
              <!-- 二三级分类 -->
              <div
                class="item-list clearfix"
                :style="{ display: currentIndex === index ? 'block' : 'none' }"
              >
                <div
                  class="subitem"
                  v-for="item2 in item1.categoryChild"
                  :key="item2.categoryId"
                >
                  <dl class="fore">
                    <dt>
                      <a :data-categoryName="item2.categoryName" :data-category2id="item2.categoryId">{{ item2.categoryName }}</a>
                    </dt>
                    <dd>
                      <em
                        v-for="item3 in item2.categoryChild"
                        :key="item3.categoryId"
                      >
                        <a :data-categoryName="item3.categoryName" :data-category3id="item3.categoryId">{{ item3.categoryName }}</a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
        </transition>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import throttle from 'lodash/throttle.js'
import { mapState } from 'vuex'
export default {
  name: 'TypeNav',
  data () {
    return {
      currentIndex: -1,
      show:true
    }
  },
  computed: {
    // ...mapState('home', ['cateList'])
    ...mapState({
      cateList: (state) => state.home.cateList
    })
  },
  created () {
    // 避免重复调取接口 可以使用本地储存或者把方法放到APP.vue中 根组件只执行一次
    // this.getCateList()
    if (this.$route.name !== 'home') {
      this.show = false
    }
  },
  methods: {
    // ...mapActions('home', ['getCateList']),

    // 背景色改变的方法
    // changItemStyle (index = -1) {
    //   this.currentIndex = index
    // }
    // 背景色改变的方法:节流版
    changItemStyle: throttle(function (index) {
      this.currentIndex = index
    }, 50),
    // 去搜索页面 时间委托 并且使用 e.target.dataset
    goSearch(e){
      // console.log('e:', e.target.dataset)
      // 拼接params和query参数
      const {categoryname,category1id,category2id,category3id} = e.target.dataset
      const location ={name:'search'}
      const query = {categoryName:categoryname}
      if (categoryname) {
        if (category1id) {
          query.category1Id = category1id
        }else if (category2id) {
          query.category2Id = category2id
        }else{
          query.category3Id = category3id
        }
        if (this.$route.params) {
          location.params = this.$route.params
          location.query = query
          this.$router.push(location)
        }
      }
    },
    // 鼠标移除事件
    handleLeave(){
      this.currentIndex = -1
      if (this.$route.name !== "home") {
        this.show = false
      }
    }
  }
}
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            _height: 200px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }
          // CSS样式显示隐藏二三级分类
          // &:hover {
          //   .item-list {
          //     display: block;
          //   }
          // }
        }
        .cur {
          background-color: skyblue;
        }
      }
    }

    .fade-enter-active,
    .fade-leave-active{
      transition: all 1s;
    }
    .fade-enter,
    .fade-leave-to{
      opacity: 0;
    }
  }
}
</style>
